TUNNELING METHODS UNDER STUDY COULD CUT RAIL TRANSIT COSTS

THE DEVELOPMENT OF IMPROVED METHODS OF TUNNEL EXCAVATION AND CONSTRUCTION SPONSORED BY DOT ARE REVIEWED. A METHOD OF COMBINING HIGH-PRESSURE WATER JET WITH AN EXISTING CUTTER TO SEE IF WATER-JET KERFING CAN IMPROVE HARD-ROCK CUTTING WILL BE INVESTIGATED. STUDIES ARE CONTINUING ON A LASER-BEAM DEVICE THAT PROVIDES KERFS AND THERMAL CRACKING. EFFORT IS ALSO BEING EXPENDED IN THE DEVELOPMENT OF AN 800,000-PSI WATER CANNON TO PRODUCE A "CLEAN" SHOCK EFFECT THAT COULD ELIMINATE BLASTING. DOT IS ALSO EVALUATING THE POTENTIAL OF THE SUBTERRENCE WHICH IS A HIGH-POWERED ROCK-MERITING PROBE. AN ADVANCED SUBTERRENE, POWERED BY ELECTRICITY OR NUCLEAR ENERGY, WOULD THEORETICALLY BE ABLE TO MELT THROUGH ROCK AND FORM A LINING OF MOTLEN GLASS AS IT EXCAVATES. INITIAL TESTS INDICATE THE VIABILITY OF THE CONCEPT. ANOTHER AREA OF INTEREST IS THAT OF PRECAST WALL PANELS (FOR CUT-AND-COVER CONSTRUCTION) WHICH CAN BE JOINED (USING TONGUE-AND-GROOVE DESIGN) AND INSTALLED VERY CLOSE TO BUILDINGS WITHOUT SPECIAL UNDERPINNING REQUIREMENTS. SLIPFORMED TUNNEL LININGS ARE ALSO BEING INVESTIGATED. REGULATED-SET CONCRETE AND FIBER-REINFORCED CONCRETE, IT IS CLAIMED, COULD BE PUMPED OR EXTRUDED. EVALUATORY STUDIES ARE BEING CONDUCTED ON PNEUMATIC AND HYDRAULIC TRANSPORT. WORK IS IN PROGRESS ON MUCK-REMOVAL SYSTEMS COMPRISING CONTINUOUS FLOW DEVICES. AN AIR-JET PROCESS FOR TRANSFORMATION OF MUCK INTO A ROCK WOOL-LIKE SUBSTANCE IS BEING EXAMINED. A CONTRACTOR EDUCATION PILOT PROJECT AND A STUDY OF CONTRACTING PROCEDURES IS ALSO UNDERWAY.

Media Info

  • Pagination: p. 15
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00236711
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 16 1981 12:00AM